Functional magnetic resonance imaging (fMRI) utilizes a standard magnetic resonance imaging (MRI) machine to identify regions of cerebral function during specific tasks. The test measures changes in blood oxygen levels associated with increased blood flow to regions of active brain function during a particular task. Physicians and scientists design protocols in which a patient performs a task repetitively to activate a particular area of brain (for instance, lifting the left index finger). By analyzing this data, the region or regions of brain involved in performing the task can be identified. This test is increasingly being utilized, like magnetoencephalography (MEG), in the pre-operative planning of patients undergoing neurosurgical procedures in regions near functional cortex.